Hermetically sealed motor compressors of various designs are well known in the art. These designs include both the piston/cylinder types and scroll types. The present invention applies equally well to all of the various designs of motor compressor units, and it will be described for exemplary purposes embodied in both a hermetically sealed scroll type fluid machine and a hermetically sealed piston/cylinder type fluid machine.
A scroll type fluid machine has a compressor section and an electrical motor section mounted in a hermetic shell with fluid passages being formed through the walls of the hermetic shell. The fluid passages are normally connected through pipes to external equipment such as, for example, an evaporator and condenser when the machine is used in a refrigeration system.
The scroll type compressor section has a compressor which is comprised of a non-orbiting scroll member which is mated with an orbiting scroll member. These scroll members have spiral wraps formed in conformity with a curve usually close to an involute curve so as to protrude upright from end plates. These scroll members are assembled together such that their wraps mesh with each other to form therebetween compression chambers. The volumes of these compression chambers are progressively changed in response to an orbital movement of the orbiting scroll member. A fluid suction port communicates with a portion of the non-orbiting scroll member near the radially outer end of the outermost compression chamber, while a fluid discharge port opens in the portion of the non-orbiting scroll member close to the center thereof. An Oldham's ring mechanism is placed between the orbiting scroll member and the non-orbiting scroll member so as to prevent the orbiting scroll member from rotating about its own axis.
The non-orbiting scroll member is secured to the main bearing housing by means of a plurality of bolts extending therebetween which allow limited relative axial movement between the bearing housing and the non-orbiting scroll member.
The orbiting scroll member is driven by a crankshaft so as to produce an orbiting movement with respect to the stationary scroll member. Consequently, the volumes of the previously mentioned chambers are progressively decreased to compress the fluid confined in these chambers, and the compressed fluid is discharged from the discharge port as the compression chambers are brought into communication with the discharge port.
A separation plate extends across the interior of the hermetic shell in order to divide the shell into a suction pressure zone and a discharge pressure zone. As a safety feature of the compressor, an IPR valve is indirectly attached to the separator plate by being threadingly received in a fitting which extends through the separation plate. The IPR valve will release discharge pressure to suction pressure when the discharge pressure exceeds a predetermined value.
A piston/cylinder type fluid machine has a compressor section and an electrical motor section mounted in a hermetic shell with fluid passages being formed through the walls of the hermetic shell. Similar to the scroll compressor described above, the fluid passages are normally connected through pipes to external equipment.
The piston/cylinder type fluid machine has a compressor which is comprised of a compressor body having one or more pistons mounted for reciprocal movement within cylinders extending through the compressor body. The piston moves from a lower position where fluid is allowed to enter the cylinder at a suction pressure to an upper position where the fluid within the cylinder its compressed between the piston and a cylinder head. The cylinder head normally includes one or more discharge valves which release the compressed fluid to the discharge pressure portion of the compressor.
The pistons are driven by a crankshaft so as to produce the reciprocating movement of the piston within the cylinder. Consequently, compressed fluid is delivered to the discharge pressure portion of the compressor with each movement of the piston between its lower and upper positions.
The interior of the hermetic shell for a piston/cylinder type fluid machine is normally at suction pressure. The compressor delivers compressed fluid to the discharge pressure portion of the compressor which normally includes a discharge conduit circuitously routed through the hermetic shell and a discharge muffler located within the hermetic shell at a location along the discharge conduit to facilitate the packaging of the system. As a safety feature of the compressor, an IPR valve is indirectly secured to the muffler by being threadingly received in a fitting which extends through the wall of the discharge muffler. The IPR valve will release discharge pressure to suction pressure within the hermetic shell when the discharge pressure exceeds a predetermined value.
While these prior art methods of indirectly attaching the IPR valve to a particular component have performed satisfactorily in the market, there is a never ending need to reduce the costs and complexities of the compressor assemblies.
Accordingly, what is needed is a means for directly fixedly attaching an IPR valve to either a separation plate in a scroll compressor or a discharge muffler in a piston/cylinder compressor. The attachment must be capable of withstanding the required pressures generated during the operation of the compressor while at the same time simplifying the assembly of the compressor and reducing the number of components required.